Subject Name Environmental Science and Engineering Unit ENVIRONMENTAL

Subject Name : Environmental Science and Engineering Unit : ENVIRONMENTAL POLLUTION Subject Code : GE 8291 Branch : ECE section (A & B) Semester : IV Prepared by : K. SAKTHIKUMAR Approved by : HOD – chemistry DEPARTMENT OF CHEMISTRY MOHAMED SATHAK ENGINEERING COLLEGE KILAKARAI.

AIR POLLUTION Defined as the presence of one (or) more contaminants like dust, smoke, mist and odour in the atmosphere which causes damage to plants, animals and human beings. Composition of air: N- 78%, O 2 – 21%, Argon <1%, CO 2, 0637%, Tracer of O 3, He, NH 3. SOURCES: (i) National Source: Volcanic eruption, forest fires, biological decay, radioactive materials. (ii)Man-made: Thermal power plants, Automobile emission, forest fires , fuel burning, agricultural activities. CLASSIFICATION OF AIR POLLUTANTS Primary pollutions, secondary pollutions Primary Pollutants: Pollutants emitted directly into the atmospheres in harmful form. E. g. : CO, NO, SO 2 etc.

Secondary Pollutants: Some of primary pollutnts react with one another (or) with basic Components of air to form new polluants. E. g. : NO/No 2 Moist HNO 3/NO 3 etc. Indoor Air Pollutants: These are primary air pollutants Important indoor air pollutant is radon gas. Sources of I. A. Pollutants: Radon gas in emitted by the building materials like bricks, concrete, tiles which are derived from soil containing radium. Burning fuel in the kitchens, cigarette smoke liberates pollutants like CO, SO 2. Common Air pollutants sources and their effects CO – formed by the incomplete combustion of carbon containing fuels. 2 C + O 2 ------> 2 CO Human Sources – Cigarette smoking, burning fossil fuels. 77% Co comes from motor vehicle exhaust.

Health Effect- Reacts with hemoglobin and reduces the ability of to carry O 2 to body cells and tissues, which causes headaches and anemia. NO 2 – It gives photochemical smog. In atmosphere it reacts with moisture to form HNO 3. No 2 + Moisture ------> HNO 3 Human sources: Fossil fuel burning in motor vehicles and power industrial plants. Effect Health, Lung irritation and damage Environment effect: HNO 3 corrode metals and eat away stone on buildings, statues, NO 2 damages fabrics. SO 2 - Formed mostly by the combustion of sulphur containing fossil fuels like coal and oil. It is converted to H 2 SO 4 in the atmosphere. It is major component of acid deposition.

• • • Human Source- Coal burning in power plants and industrial process. Health effects- Breathing problems. Environment effect – Reduce visibility, H 2 So 4 damages trees, soil and aquatic life. Suspended particulate Matter (SPM) -It includes varieties of particles and droplets. Human Sources – Burning coal in power and industrial plants. Burning diesel and other fuels in vehicle, agriculture, unpaved roads construction. Health Effect – Nose and throat irritation, lung damage, asthma, reproductive problems and cancer. Environment effect – Reduce visibility, acid deposition & H 2 SO 4 droplets damage trees. O 3 - Highly reactive irritating gas in the troposphere. It is major component of photo chemical smog. Human Source- Chemical reactions with volatile organic compounds and nitrogen oxides. Environment effect – Moderates the climate. Photochemical smog: Any chemical reaction activated by light is called photochemical reaction. Photochemical smog is a mixture of more than 100 primary and secondary pollutants formed under the influence of sunlight. Its formation begins inside automobile engines and the boilers in coal burning power and industrial plants.

Health Effect – Breathing problems, cough, ENT irritation, heart diseases etc. , Environment effect – Smog can reduce visibility. 7 Lead – Solid toxic metal and its components emitted into the atmosphere as a particulate matters. Human Source- Paint, lead manufacture, storage batteries, leaded petrol. Health Effect – Mental retardness (in children) digestive and other health problems. Some lead containing chemicals causes cancer in test animals. Environment effect – Can harm wild life. Controlling air Pollution Controlling at the sources: 1. Use only unleaded petrol 2. Use fuels that have low sulphurs and ash containing. 3. Plant trees along busy streets because they remove particulates and CO and absorb noise 4. Industries and waste disposal should be outside the city area.

5. Use catalytic converters to control the emission of CO and hydrocarbon. Control Measures in industries: 1. Emission rates should be restricted to permissible levels in all industries. 2. Air pollution control equipment should be incorporated in plant layout 3. Monitering of the atmosphere for the pollutants should be carried out continuously to know the emission levels. 4. Scrubber, cyclone separator, bag house filter and electrostatic precipitators must be used in manufacturing process to retain harmful materials that must be disposed of safely. 1. The disposal of the collected air pollutants are equally important for controlling air pollution.

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